Mustang 428 Cobra Jet Registry Forum

Guys, I have a question around the Upper Contol arm ball joints for a CJ Mach 1. A while back I purchased a correct fully restored set of Upper and Lower arms. The upper has the correct riveted ball joints and while going through our certification shop they picked up some play on both my upper joints. The car has done about 300 miles since a full rotisserie resto. I was shocked to see the play but on checking the workshop manual the ball joint play specification is .250 thou, 1/4" :-\. Once I confirmed the play spec, they passed the car, obviously it had less than that. My question is, has anyone else come across this and how much have you seen? The next question is does anyone know who restores the original arms back to concours with new ball joints?

It's been a real long time but I do remember that the allowed slop was quite big. I seem to recall that where the 1/4" was measured was up for argument. Hey, us poor kids couldn't afford buying hard parts that you couldn't see.

Don't be too quick to replace them. I suspect that all of the parts are stamped. Thus the fit when new might be snug but the actual contact area could be small. As you drive, those small areas are likely "wearing" to matching the mating parts over a larger area. So I think the rate of wear will slow down a lot. The fastest wear is behind you. My advice would be to make sure each ball joint stays full of the correct grease.

The original design Ford ball joints did have quite a lot of clearance in them, and I can remember a lot of cars back in the day having those ball joints replaced, unnecessarily, when they were nearly new. If you have original Ford ball joints, and they meet the shop manual spec, then I'm sure they are fine. I don't think that any of the aftermarket ball joints have the same sort of clearance so the shop manual spec wouldn't apply, so you might want to be sure what you have.

"Rare Parts" was doing the riveting once upon a time, but if you want original Ford ball joints you'd have to supply them.

My worthless two cents…1/4 inch 'slop' in a ball joint in my opinion is not acceptable, and could be potentially dangerous. I have seen many Mustangs with broken upper ball joints, and the resulting damage is not what you want. Losing control of your vehicle is….you get my concern. "Correct" is not necessarily 'Good' in my book. Then again, its your call….

My worthless two cents…1/4 inch 'slop' in a ball joint in my opinion is not acceptable...

The key point is that the 1/4" max measurement is taken at the wheel rim with the ball joint unloaded. The way the Ford ball joints were made they were very loose when unloaded, for whatever reason, but relatively tight when loaded. A new one right out of the box was the same way, so they were designed to be that way. I've never seen a replacement ball joint that was like that, and mechanics back in the day were weirded out by what appeared to be excessive clearance .

My worthless two cents…1/4 inch 'slop' in a ball joint in my opinion is not acceptable...

The key point is that the 1/4" max measurement is taken at the wheel rim with the ball joint unloaded. The way the Ford ball joints were made they were very loose when unloaded, for whatever reason, but relatively tight when loaded. A new one right out of the box was the same way, so they were designed to be that way. I've never seen a replacement ball joint that was like that, and mechanics back in the day were weirded out by what appeared to be excessive clearance .

Ok, I will bite. What IS the intended purpose for it to be 'loose' when unloaded?

...Ok, I will bite. What IS the intended purpose for it to be 'loose' when unloaded?

I really don't have any idea, crossboss. I do remember that if you put a new car on the rack and checked it, it would appear that the ball joints were loose, and a lot of gas station mechanics were replacing ball joints that didn't actually need replacing according to the shop manual. I suspect that there was no "intended purpose", but more likely it was just a consequence of the internal design. I've never looked inside one.

The entire front end under a Mustang strikes me as a bit of a mess. It was probably OK for a 144 ci Falcon, but somewhere between there and stuffing an FE into a Mustang someone should have figured that something better might have been a good idea.

Thanks for your reply. I agree, most likely Ford continued with the ancient (aka cheap) design of the previous models and 'applied' it to later models like the big block, Boss, and Mach-1s. Yes, the suspensions were upgraded, yet some components were still a mess. That alone IS the reason 'I' would never drive a car with 'loose' suspension components. Like I said 'correct' is not 'good' in my book when it applies to a potentially dangerous situation.

If I am not mistaken all of the FOMOCO suspension pieces were manufactured by MOOG or TRW for Ford. That being said, MOOG still offers replacement UCA for less than $100 ea. They are the three rivet variety, but have riveted ball joints that are brand new. I would consider your planned use of the car, judged shows vs. driving, when considering replacement parts.

If your ball joints look like these, I'd go with the specs in the shop manual:https://www.ebay.com/itm/2-NOS-1967-1968-1969-Mustang-Shelby-Cougar-Fairlane-Upper-Ball-Joints-OEM-FORD/273508704120?epid=9021952508&hash=item3fae639f78:g:OBoAAOSwCA5bXyPp:sc:USPSPriorityFlatRateBox!95497!US!-1:rk:13:pf:0 (https://www.ebay.com/itm/2-NOS-1967-1968-1969-Mustang-Shelby-Cougar-Fairlane-Upper-Ball-Joints-OEM-FORD/273508704120?epid=9021952508&hash=item3fae639f78:g:OBoAAOSwCA5bXyPp:sc:USPSPriorityFlatRateBox!95497!US!-1:rk:13:pf:0)

If your ball joints don't look like those, then I'd be very suspicious if they had any perceptible clearance at all. Notice that the NOS Ford joints are very distinctive in the way that they are constructed, and I've never seen an aftermarket part exactly like them.

I'd agree with crossboss that if you're seeing anything even remotely like 1/4" clearance in anything other than what is known to be an original Ford design joint it would be good reason for concern...in that case you don't want to be following the shop manual.

Kiwi states his UCA's have the correct ' riveted ' upper ball joints. Does not state the ball joints are OE/correct ? So as Gerald has asked; check the ball joints for authenticity. The Shop Manual spec's may not apply ? Could also ask the manufacturer for the ball joint info ? Pictured are a pair of the today's Moog upper replacements and they have zero play/flex and in fact are quite rigid. The boot is an aftermarket Drake C7OZ-3105-B. Brian

If the stamped metal around the joint looks at the very least similar to the original old ball joint. Would it be a horrible big leap to think the inside design is based upon the Ford joint? Other that destroying a new joint to see what the inside design is, how is a guy to know if its a loose Ford design or not? For that matter, has anyone cut a Ford joint apart?

...Would it be a horrible big leap to think the inside design is based upon the Ford joint?...

It might be :). That's really the reason I brought it up. I think it might be a serious mistake to use the 1/4" max spec for radial play from the shop manual, for anything other than an original Ford ball joint. I don't have any answers as to how to be sure if it is or it isn't. If they aren't original Ford ball joints, I guess better safe than sorry? Were it not for the Ford shop manual, I'd never want to see a ball joint with 1/4" of radial play...

I can understand the reasoning. But if a larger company i.e. Moog is making a replacement ball joint for a 60/70's Ford product. Is there any industry "best practice" to use/follow the Ford design. Hey I get that there is a huge leap there. But lacking inspection criteria from Moog. What inspection guidelines does a guy have to fall back on? The only data out there is likely going to be the Ford manual. I remember having a car that the mechanic during the yearly safety inspection didn't like the unloaded play. Car drove within reason. Another mechanic came by & said it was still in spec. The next year a different shop never said a word. Does this turn into a yearly parts swapping contest? Many of us had a car or two back in the day that traveled 100k miles with the original ball joints. Can the design be that horrible just because we don't like it?

I don't think that there's anything wrong with the original Ford ball joints, and so long as they are within the 1/4" radial play spec in the shop manual I wouldn't hesitate to use them. I've had them go 100K+ miles without any apparent problem. It does look at bit odd when you check them though.

As I remember the issue from back in the day, customers were wanting their ball joints replaced, under warranty, because some outside mechanic, usually at a gas station, told them that they were worn out and couldn't pass state safety inspection. Unless you were following the shop manual, they did appear to be worn out, but in fact they were usually well within the spec and there was nothing to be gained by replacing them. I'll bet the confusion led to millions of them being replaced unnecessarily.

What I don't know, and don't know how you'd find out, is if any of the aftermarket ball joints (or for that matter maybe some later Ford replacement ball joints), are safe to use based on the original 1/4" spec in the shop manual. My hunch is no. In most cases I would think that any perceptible play would be unacceptable. When the shop manual was written I don't think anyone considered what would be appropriate for some aftermarket part someone might use 50 years later.

True, I'm sure that Ford didn't consider the aftermarket parts. But is there any guidance from big outfits like Moog on how to inspect Moog ball joints? Seems odd that they wouldn't have inspection data if their joints did not follow Fords lead. So back in a circle, it may well be that the Ford manuals might be the default inspection standard. Do you remember the epoxy fix that you pumped thru the grease fitting hole? I bet that only "fixed" the hanging slop. Probably didn't help drivability.......very much. Just gotta love all the thinking we do now over cars that we used to just jump in & go.

I've never seen inspection criteria for any aftermarket anything so I don't consider it odd. The factory shop manual is what any dealership technician would use. As they say "parts is parts". Back in the day it was not uncommon for the guys at a Brake - O or Sears automotive shop to put my car on a lift, then pry up and down on the A - arm with a crowbar to determine if they needed to try and sell me a front end rebuild when I was there buying tires.

Those upper ball joints never had enough play to be rejected. I always ended up changing upper A - arms to fix the annoying squeak of inner upper A - arm bushings that had run out of grease. The upper ball joints seemed to last forever if they were greased. They never in my experience wore out, even after several hundred thousand miles.

True, I'm sure that Ford didn't consider the aftermarket parts. But is there any guidance from big outfits like Moog on how to inspect Moog ball joints? Seems odd that they wouldn't have inspection data if their joints did not follow Fords lead. So back in a circle, it may well be that the Ford manuals might be the default inspection standard. Do you remember the epoxy fix that you pumped thru the grease fitting hole? I bet that only "fixed" the hanging slop. Probably didn't help drivability.......very much. Just gotta love all the thinking we do now over cars that we used to just jump in & go.

Thanks Guys, that really struck up some serious conversation and yes, I'm a little concerned about the play that has been found despite the Factory specs. I got in touch with the person who rebuild my upper control arms, Gary Erickson, and he to is a little confused as to why these should have play? I will post some photos to show what I have and maybe then we can tell if they are as original as I thought. At the time of my research, I found these to have 4 Rivets when they came out of the factory, but I could be wrong?

The car has been in shows and is driven from time to time, but importantly, I want it to be safe and as correct as possible.

Its because of this site and the wealth of knowledge that makes us question what we do or have when rebuilding these cars. Thanks to everyone who posted a response and Ill keep you posted on how I get on.